JP2006053564A - Plasma display apparatus and driving method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display apparatus capable of preventing surface discharge between scan electrodes and sustain electrodes during an initialization period, while reducing the initialization period and a method for driving the same. <P>SOLUTION: The plasma display apparatus includes a scan electrode driving section of applying a reset pulse to the scan electrode, and a timing control section for altering the end point of falling of the reset pulse applied with the scan electrode driving section. The timing control section alters the end point of raising of the reset pulse. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma display apparatus and a driving method of the plasma display apparatus, and more particularly to a plasma display apparatus related to contrast and a driving method of the plasma display apparatus.

  The plasma display apparatus displays an image by causing the phosphor to emit light when the inert mixed gas such as He + Xe, Ne + Xe, or He + Xe + Ne is discharged. Such a plasma display device is not only easily made thin and large, but also has improved image quality due to recent technological development.

  FIG. 1 is a waveform diagram of drive pulses of a general plasma display device. As shown in FIG. 1, a general plasma display apparatus has a setup period and a set-down period for initializing the entire screen, an address period for selecting a cell, and a sustain period for maintaining the discharge of the selected cell. It is driven separately. At this time, Y represents a scan electrode, Z represents a sustain electrode, and X represents an address electrode.

  During the setup period, the rising ramp pulse (Ramp-up) is simultaneously applied to all the scan electrodes (Y). This rising ramp pulse (Ramp-up) causes a setup discharge, which is a weak discharge form, to occur in the cells of the entire screen, and wall charges accumulate in the cells. During the set-down period, a ramp-down pulse (Ramp-down) falling from a positive voltage lower than the peak voltage of the ramp-up pulse (Ramp-up) is simultaneously applied to the scan electrode (Y). Falling ramp pulse (Ramp-down) causes a weak erasing discharge in the cell to erase the wall charge generated by the setup discharge and unnecessary charge in the space charge, and uniforms the wall charge in the cells of the entire screen. It becomes to remain in.

  In the address period, scan pulses (scan) are sequentially applied to the scan electrode (Y), and a positive data pulse (data) is applied to the address electrode (X) in synchronization with the scan pulse applied to one scan electrode. Is done. Address discharge is generated in the cell to which the data pulse (data) is applied while the voltage difference between the scan pulse (scan) and the data pulse (data) and the wall voltage generated during the setup period and the set-down period are added.

  On the other hand, a positive direct current voltage having a sustain voltage level (Vs) is supplied to the sustain electrode (Z) between the set-down period and the address period.

  In the sustain period, a sustain pulse (sus) is alternately applied to the scan electrode (Y) and the sustain electrode (Z). The cell selected by the address discharge is applied between the scan electrode (Y) and the sustain electrode (Z) every time the sustain pulse (sus) is applied while the wall voltage and the sustain pulse (sus) are applied. A surface discharge type sustain discharge occurs.

  Finally, after the sustain discharge is completed, an erase ramp waveform (erase) having a small pulse width is supplied to the sustain electrode (Z) to erase wall charges in the cell.

  Meanwhile, the conventional plasma display apparatus has a problem that the contrast is lowered by the light generated during the setup period and the set-down period.

  In more detail, the rising ramp pulse (Ramp-up) supplied during the setup period causes the scan electrode (Y) and the address electrode (X) to fall between the scan electrode (Y) and the sustain electrode (Z). Discharge occurs in the meantime. In particular, the discharge generated between the scan electrode (Y) and the sustain electrode (Z) by the rising ramp pulse (Ramp-up) and between the scan electrode (Y) and the address electrode (X) is the second half of the setup period ( It happens intensively at Td).

  As a result, as shown in FIG. 2, negative wall charges are formed on the scan electrode (Y), and positive wall charges are formed on the sustain electrode (Z). Here, it is known that the discharge that occurs between the scan electrode (Y) and the sustain electrode (Z) occurs at a lower voltage than the discharge that occurs between the scan electrode (Y) and the address electrode (X). As shown in FIG. 1, the discharge that occurs between the scan electrode (Y) and the sustain electrode (Z) is applied with a setup pulse applied to the scan electrode (Y) in the second half of the setup period (Td). This occurs because a ground level voltage is applied to increase the voltage difference between the scan electrode (Y) and the sustain electrode (Z).

  Since the scan electrode (Y) and the sustain electrode (Z) are formed on the upper substrate, the light generated by the discharge between the scan electrode (Y) and the sustain electrode (Z) is generated between the scan electrode (Y) and the address electrode (X). It is easier to reach the viewer than the light generated by the discharge between them. Therefore, the amount of light traveling toward the observer is due to the discharge generated between the scan electrode (Y) and the address electrode (X) due to the amount of light generated between the scan electrode (Y) and the sustain electrode (Z). Greater than the amount of light. As a result, the amount of light emission increases during the setup period and the set-down period, thereby degrading the contrast characteristics.

  In order to prevent such deterioration of contrast characteristics, a driving waveform of the conventional plasma display device shown in FIG. 3 has been proposed.

  FIG. 3 is a waveform diagram showing a driving method of a conventional plasma display apparatus, and FIG. 4 shows an energy recovery circuit used in the conventional plasma display apparatus.

  As shown in FIG. 3, the conventional plasma display apparatus is divided into an initialization period for initializing the entire screen, an address period for selecting a cell, and a sustain period for maintaining the discharge of the selected cell. Driven.

  The initialization period includes a setup period and a set-down period. During the setup period, the rising ramp pulse (Ramp-up) is simultaneously applied to all the scan electrodes (Y).

 Due to the rising ramp pulse (Ramp-up), a weak discharge occurs in the cells of the entire screen, and wall charges are formed in the cells. At this time, the base voltage is applied to the sustain electrode (Z) in the first half of the setup period. In the second half of the setup period (Td), the sustain electrode (Z) is in a floating state (floating state) until the setup ramp pulse (Ramp-up) reaches the peak voltage (V2) (time Td). ) The floating state of the sustain electrode (Y) is maintained. When the sustain electrode (Z) is in a floating state, a predetermined voltage is induced in the sustain electrode (Z). That is, a predetermined ramp voltage is induced in the sustain electrode (Z) by the voltage of the rising ramp pulse (Ramp-up).

  At this time, the sustain electrode (Z) is brought into a floating state by the energy recovery circuit shown in FIG. The panel capacitor (Cp) is equivalent to a discharge cell. In the first half of the setup period, the fourth switch (S4) is turned on, and the ground potential (GND) is applied to the sustain electrode (Z). In the second half (Td) of the setup period, the fourth switch (S4) is turned off. At this time, the first to third switches (S1, S2, S3) also maintain the turn-off state. As a result, the sustain electrode (Z) enters a floating state.

 In the set-down period, the third switch (S3) is turned on and the sustain voltage level (Vs) is applied to the sustain electrode (Z).

  In this way, if the sustain electrode (Z) is in a floating state, no discharge occurs between the scan electrode (Y) and the sustain electrode (Z) in the second half (Td) of the setup period, and the scan electrode (Y) Discharge occurs only between the address electrodes (X). That is, in the second half of the setup period (Td), the sustain electrode (Z) is in a floating state and a predetermined ramp voltage is induced, so that the voltage difference between the scan electrode (Y) and the sustain electrode (Z) is increased. The surface discharge occurring between the scan electrode (Y) and the sustain electrode (Z) is prevented. Therefore, the luminance in the initialization period is lowered and the contrast is improved.

  However, the conventional plasma display apparatus has a period (Td) in which the sustain electrode (Z) is in a floating state in order to prevent surface discharge generated between the scan electrode (Y) and the sustain electrode (Z) during the setup period. ) Is required. Therefore, the conventional plasma display apparatus and the conventional driving method have a limit in reducing the initialization period.

  An object of the present invention is to provide a plasma display apparatus and a driving method thereof that can prevent a surface discharge between a scan electrode and a sustain electrode during the initialization period while reducing the initialization period.

  The plasma display apparatus of the present invention includes a plasma display panel including a scan electrode, a scan electrode driver that applies a reset pulse to the scan electrode, and a timing control that changes a falling end point of the reset pulse applied by the scan electrode driver Part.

  The plasma display apparatus of the present invention includes at least one plasma display panel including a scan electrode, a scan electrode driving unit that applies a reset pulse to the scan electrode, and a falling end point of the reset pulse applied by the scan electrode driving unit. It includes a timing control unit that changes differently in subfields.

  The driving method of the plasma display apparatus of the present invention includes a step of starting application of a reset pulse to the scan electrode, a step of changing a falling end time of the reset pulse, and ending application of the reset pulse to the scan electrode Including the steps of:

  The timing control unit may change the rising end time of the reset pulse.

  The timing control unit may control the end point of falling of the reset pulse differently in at least one subfield.

  The timing controller may control the rising end point of the reset pulse and the falling end point of the reset pulse differently in at least one subfield.

  The scan electrode driver may maintain the same slope of the falling ramp pulse included in the reset pulse in each subfield.

  The scan electrode driver maintains an equal slope of the rising ramp pulse included in the reset pulse in each subfield, and maintains an equal slope of the downward ramp pulse included in the reset pulse in each subfield. Features.

  The scan electrode driving unit may cause the scan electrode to be in a floating state at the end of the lowering.

  The timing control unit may change the falling end time of the reset pulse according to the rising end time of the reset pulse.

  The timing controller may change the lowering end time according to the rising end time of the reset pulse in at least one subfield.

  The driving method of the plasma display apparatus according to the present invention includes a step of starting application of a reset pulse to the scan electrode, a step of changing a falling end point of the reset pulse, and ending application of the reset pulse to the scan electrode. Including stages.

  The method further includes a step of changing the rising end time of the reset pulse before the step of changing the falling end time of the reset pulse.

  The reset pulse end point may be controlled differently in at least one subfield.

  The rising end time of the reset pulse and the falling end time of the reset pulse are controlled differently in at least one subfield.

  The slope of the falling ramp pulse included in the reset pulse is maintained equal in each subfield.

  The slope of the rising ramp pulse included in the reset pulse is maintained equal in each subfield, and the slope of the falling ramp pulse included in the reset pulse is maintained equal in each subfield.

  The scan electrode is in a floating state at the end of the descent.

  The falling end point of the reset pulse is changed according to the rising end point of the reset pulse.

  The descent end time is changed according to the rise end time of the reset pulse in the at least one subfield.

  The lower end of the reset pulse and the lower end of the reset pulse are made earlier as the sub-field is a low gradation subfield.

  The plasma display apparatus and driving method according to the present invention can reduce driving time while improving contrast.

  Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 5 is a block diagram of the plasma display apparatus according to the present invention. As shown in FIG. 5, the plasma display apparatus according to the present invention includes a plasma display panel 510, a scan electrode driver 520, and a timing controller 530.

  The plasma display panel 510 includes a scan electrode (Y), a sustain electrode (Z), and an address electrode (X).

  The scan electrode driver 520 applies a reset pulse to the scan electrode (Y) to form a uniform wall charge inside the entire cell constituting the plasma display panel 510, and applies a scan pulse to cause a sustain discharge. And a sustain pulse is applied to cause a sustain discharge in the selected cell. At this time, the reset pulse is preferably composed of a rising ramp pulse and a falling reset pulse.

  The timing control unit 530 changes the falling end point of the reset pulse applied by the scan electrode driving unit. The timing controller 530 can adjust the amount of discharge that occurs between the scan electrode (Y) and the sustain electrode (Z) by changing the end point of the reset pulse.

  Further, the timing control unit 530 can change the end point of the reset pulse falling in at least one subfield.

  In addition, the timing controller 530 can change not only the falling end point of the reset pulse but also the rising end point of the reset pulse, whereby the amount of discharge generated between the scan electrode (Y) and the sustain electrode (Z). Can be controlled more precisely.

  Further, the timing controller 530 can change the rising end point and the falling end point of the reset pulse differently in at least one subfield.

  The timing controller 530 also changes the end point of the reset pulse falling according to the end point of the rise of the reset pulse. Desirably, the timing control unit 530 also sets the reset pulse end point earlier if the reset pulse end point rises earlier.

  In addition, the timing control unit 530 changes the falling end point of the reset pulse according to the rising end point of the reset pulse in at least one subfield. Desirably, the timing control unit 530 makes the descent end point earlier if the rise end point of the reset pulse is made earlier. The adjustment of the end point of the descent according to the end point of the rise by the timing control unit 530 as described above will be described in the following embodiments.

  At this time, the scan electrode driver 520 maintains the gradient of the rising ramp pulse or the gradient of the falling ramp pulse equal in each subfield even if the rising end time or falling end time of the reset pulse changes. That is, the scan electrode driving unit 520 applies the falling ramp pulse at the end of the rising by the control of the timing control unit 530 while applying the rising ramp pulse that rises to a predetermined slope, thereby increasing the rising voltage level of the reset pulse. Adjust.

  In addition, the scan electrode driver 520 resets the scan electrode (Y) to be in a floating state at the end of the lowering by the control of the timing control unit 530 while applying the falling ramp pulse that falls to a predetermined slope. Adjust the voltage drop level. The description of the floating state of the scan electrode (Y) will be described in detail in the following embodiments.

  Reference numerals 540 and 550 are an address electrode driver 540 and a sustain electrode driver 550, respectively. The address electrode driver 540 applies a corresponding address pulse to the address electrode (X) in synchronization with the scan pulse applied to one scan electrode by the scan electrode driver 520. The sustain electrode driver 550 applies a positive DC voltage to the sustain electrode (Z) when the falling ramp pulse and the scan pulse forming the reset pulse are applied to the scan electrode (Y), and also applies to the scan electrode (Y). A sustain pulse alternated with the applied sustain pulse is applied to the sustain electrode (Z).

  Next, an embodiment of a driving method for the plasma display apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 6 is a procedure diagram of the driving method of the plasma display apparatus according to the present invention.

  In the driving method for the plasma display apparatus of the present invention, first, application of a reset pulse to the scan electrode is started (S610). When the reset pulse is composed of an ascending ramp pulse and a descending ramp pulse, the ascending ramp pulse having a predetermined slope is applied to the scan electrode (Y) first, and then the descending ramp pulse is applied to the scan electrode (Y).

  In succession, the end point of the reset pulse falling is changed by the timing controller 530 (S620). As a result, the scan electrode driver 520 stops applying the reset pulse that descends at the end of the descent and ends the application of the reset pulse (S630).

Such a process will be described in more detail through the following four embodiments.
<Embodiment 1>
FIG. 7 is a waveform diagram showing a driving method of the plasma display apparatus according to the first embodiment of the present invention. As shown in FIG. 7, in the driving method of the plasma display apparatus according to the first embodiment of the present invention, the timing controller 530 changes the reset pulse falling end point to change the set-down period.

  That is, if the minimum voltage of the ramp-down pulse applied to the scan electrode (Y) by the scan electrode driving unit 520 is changed from the fourth voltage (V4) to the third voltage (V3) by the control at the end of the fall of the timing control unit 530. The voltage difference between the scan electrode (Y) and the sustain electrode (Z) is reduced. As a result, the amount of discharge generated between the scan electrode (Y) and the sustain electrode (Z) is reduced, and the amount of light is also reduced, thereby improving the contrast. If the minimum voltage of the ramp-down pulse is changed from the fourth voltage (V4) to the third voltage (V3), there is room for the initialization period to decrease as indicated by Ts, so that the overall drive time can be reduced.

  At this time, the timing controller 530 outputs a floating control signal from the scan electrode driver 520 when the controlled reset pulse ends. Accordingly, the scan electrode driver 520 causes the scan electrode (Y) to be in a floating state.

 Accordingly, a DC voltage such as the third voltage (V3) is induced at the scan electrode (Y) by the positive DC voltage (Vdc) applied to the sustain electrode (Z).

At this time, the scan electrode driver 520 maintains the slope of the falling ramp pulse to be equal even if the end point of the lowering changes. In other words, the scan electrode driver 520 resets the scan electrode (Y) to be in a floating state at the end of the lowering by the control of the timing control unit 530 while applying the falling ramp pulse that falls at a fixed slope. Adjust the voltage drop level.
<Embodiment 2>
FIG. 8 is a waveform diagram showing a driving method of the plasma display apparatus according to the second embodiment of the present invention. The upper part of FIG. 8 shows waveforms of the prior art for comparison with the present invention, and the lower part shows waveforms of the driving method according to the second embodiment of the present invention.

  As shown in the lower end of FIG. 8, in the driving method according to the second embodiment of the present invention, the timing control unit 530 not only changes the falling end time of the reset pulse but also changes the rising end time of the reset pulse. it can.

  The amount of discharge that occurs between the scan electrode (Y) and the sustain electrode (Z) can be controlled more precisely through the change between the rising end point and the falling end point of the reset pulse. Since the change at the end of falling of the reset pulse is the same as in the first embodiment, the detailed description thereof is omitted.

  At this time, the DC voltage at the end of the ramp-down pulse falling is formed by the scan electrode (Y) being in a floating state as described in the first embodiment.

  As shown in the upper part of FIG. 8, in the conventional plasma display apparatus, the sustain electrode (Z) is brought into a floating state in the second half (Td) of the setup period. If the floating state is not achieved, the voltage difference between the scan electrode (Y) and the sustain electrode (Z) becomes so large that surface discharge occurs in the second half (Td) of the setup period.

  If the sustain electrode (Z) is in a floating state in the second half of the setup period (Td), the voltage difference between the scan electrode (Y) and the sustain electrode (Z) is almost 0V, and the scan electrode (Y) Discharge generated between the sustain electrodes (Z) is prevented. The process for accumulating sufficient wall charges inside the cells on the entire screen is almost true in the first half of the setup period.

  Therefore, if the set-down period starts at time t0, the voltage difference between the scan electrode (Y) and the sustain electrode (Z) becomes large enough to cause a surface discharge while accumulating sufficient wall charges inside the cells of the entire screen. Can be blocked. In other words, the timing control unit 530 changes the reset pulse rising end point at an appropriate timing to prevent discharge between the scan electrode (Y) and the sustain electrode (Z) while supplying sufficient charge to the entire cell. can do.

  At this time, the timing control unit 530 can adjust the end point of the descent according to the end point of the rise of the reset pulse. That is, when the timing control unit 530 extends the reset pulse rising end time to increase the voltage level of the reset pulse, sufficient wall charges are accumulated inside the cell. Therefore, the timing control unit 530 can extend the end point of the descent and erase excessive wall charges. On the other hand, when the timing control unit 530 decreases the reset pulse voltage level by accelerating the end point of the reset pulse, appropriate wall charges are accumulated in the cell. Therefore, the timing control unit 530 makes the end point of the fall earlier so that the voltage level of the ramp-down pulse is not too low.

  At this time, the scan electrode driver 520 maintains the slope of the rising ramp pulse to be equal and maintains the slope of the falling ramp pulse to be equal even if the rising end time and the falling end time of the reset pulse change. That is, the scan electrode driving unit 520 applies the falling ramp pulse at the end of the rising by the control of the timing control unit 530 while applying the rising ramp pulse that rises to a predetermined slope, thereby increasing the rising voltage level of the reset pulse. Adjust.

  In addition, the scan electrode driver 520 resets the scan electrode (Y) to be in a floating state at the end of the lowering by the control of the timing control unit 530 while applying the falling ramp pulse that falls to a predetermined slope. Adjust the voltage drop level.

As a result, the amount of discharge between the scan electrode (Y) and the sustain electrode (Z) can be minimized and the contrast can be improved. In addition, since there is room for the initialization period to be reduced, the overall drive time can be reduced.
<Embodiment 3>
FIG. 9 is a waveform diagram showing a driving method of the plasma display apparatus according to the third embodiment of the present invention. As shown in FIG. 9, in the driving method of the plasma display apparatus according to the third embodiment of the present invention, the timing control unit 530 controls the end point of the falling reset pulse differently in at least one subfield.

  That is, since the subfields are composed of different sustain pulses, the wall charge distribution after the sustain period is different for each subfield. Therefore, it is effective that the falling end point of the reset pulse is appropriately changed for each subfield, rather than the falling end point of the reset pulse being equal in all the subfields.

  At this time, the DC voltage at the end of the ramp-down pulse is formed by the scan electrode (Y) being in a floating state as described in the first embodiment.

  Further, the scan electrode driver 520 equalizes the slope of the falling ramp pulse even if the falling end point of the reset pulse changes.

Accordingly, the amount of discharge between the scan electrode (Y) and the sustain electrode (Z) can be minimized for each subfield, and the contrast can be improved. In addition, since there is room for the initialization period to be reduced, the overall drive time can be reduced.
<Embodiment 4>
FIG. 10 is a waveform diagram showing a driving method of the plasma display device according to the fourth embodiment of the present invention. As shown in FIG. 10, in the fourth embodiment of the present invention, the timing control unit 530 controls the rising end point and the falling end point of the reset pulse differently in at least one subfield.

  In particular, the timing controller 530 may adjust the end point of the fall according to the end point of the rise of the reset pulse applied in each subfield. That is, when the timing control unit 530 extends the reset pulse rising end time in a specific subfield to increase the voltage level of the reset pulse, sufficient wall charges are accumulated in the cell. Therefore, the timing control unit 530 can extend the end point of the reset pulse falling in the specific subfield to erase excessive wall charges.

  On the other hand, when the timing control unit 530 lowers the reset pulse voltage level by accelerating the end point of the reset pulse in a specific subfield, appropriate wall charges are accumulated in the cell. Accordingly, the timing control unit 530 controls the voltage level of the ramp-down pulse so as not to become too low by making the end point of the fall earlier in the specific subfield.

  In particular, since the low gradation subfield with a small number of sustain pulses has a high gradation and is less affected by the sustain discharge, the rising end point and the falling end point of the reset pulse are advanced as the lower gradation subfield.

  At this time, the DC voltage at the end of the ramp-down pulse is formed by the scan electrode (Y) being in a floating state as described in the first embodiment.

  Further, the scan electrode driver 520 maintains the slope of the rising ramp pulse to be equal and maintains the slope of the falling ramp pulse to be equal even when the rising end time and the falling end time of the reset pulse change.

  As a result, the discharge amount between the scan electrode (Y) and the sustain electrode (Z) can be minimized for each subfield, and the contrast can be advanced. In addition, since there is room for the initialization period to be reduced, the overall drive time can be reduced.

The wave form diagram of the drive pulse of a general plasma display apparatus. FIG. 2 is a diagram schematically showing wall charges accumulated in a cell immediately after a setup period and a set-down period in FIG. The wave form diagram which shows the drive method of the conventional plasma display apparatus. The figure which shows the energy recovery circuit utilized for the conventional plasma display apparatus. 1 is a block configuration diagram of a plasma display device according to the present invention. FIG. FIG. 4 is a procedure diagram of a driving method of a plasma display device according to the present invention. FIG. 4 is a waveform diagram showing a driving method of the plasma display device according to the first embodiment of the present invention. FIG. 6 is a waveform diagram showing a driving method of a plasma display device according to a second embodiment of the present invention. FIG. 6 is a waveform diagram showing a method for driving a plasma display device according to a third embodiment of the present invention. FIG. 6 is a waveform diagram showing a driving method of a plasma display device according to a fourth embodiment of the present invention.

Claims (20)

A plasma display panel including scan electrodes;
A scan electrode driver for applying a reset pulse to the scan electrode;
A timing control unit that changes a falling end point of the reset pulse applied by the scan electrode driving unit;
A plasma display device comprising: The timing control unit
The plasma display apparatus according to claim 1, wherein the rising end point of the reset pulse is changed. The timing control unit
The plasma display apparatus as claimed in claim 1, wherein the end point of the reset pulse is controlled differently in at least one subfield. The timing control unit
The plasma display apparatus according to claim 2, wherein the rising end time of the reset pulse and the falling end time of the reset pulse are controlled differently in at least one subfield. The scan electrode driving unit includes:
The plasma display apparatus as claimed in claim 3, wherein the slope of the falling ramp pulse included in the reset pulse is maintained equal in each subfield. The scan electrode driving unit includes:
The rising ramp pulse included in the reset pulse is maintained to be equal in each subfield, and the falling ramp pulse included in the reset pulse is maintained to be equal in each subfield. 4. The plasma display device according to 4. The scan electrode driving unit includes:
The plasma display apparatus as claimed in claim 1, wherein the scan electrode is brought into a floating state at the end of the descent. The timing control unit
The plasma display apparatus according to claim 2, wherein the lowering end point of the reset pulse is changed according to the rising end point of the reset pulse. The timing control unit
The plasma display apparatus of claim 4, wherein the lowering end point is changed according to the rising end point of the reset pulse in at least one subfield. A plasma display panel including scan electrodes;
A scan electrode driver for applying a reset pulse to the scan electrode;
A timing control unit that changes a falling end point of the reset pulse applied by the scan electrode driving unit differently in at least one subfield;
A plasma display device comprising: In a driving method of a plasma display device including a scan electrode,
Starting application of a reset pulse to the scan electrode;
Changing the end point of falling of the reset pulse;
Ending application of a reset pulse to the scan electrode;
A method for driving a plasma display device, comprising:   The method of claim 11, further comprising a step of changing a rising end time of the reset pulse before a step of changing the falling end time of the reset pulse.   12. The method of claim 11, wherein the end point of the reset pulse is controlled differently in at least one subfield.   13. The driving method of the plasma display apparatus according to claim 12, wherein the rising end time of the reset pulse and the falling end time of the reset pulse are controlled differently in at least one subfield.   The method of claim 13, wherein the slope of the falling ramp pulse included in the reset pulse is maintained equal in each subfield.   The rising ramp pulse included in the reset pulse is maintained to be equal in each subfield, and the falling ramp pulse included in the reset pulse is maintained to be equal in each subfield. 14. A driving method of a plasma display device according to 14.   The method of claim 11, wherein the scan electrode is in a floating state at the end of the descent.   13. The method of driving a plasma display apparatus according to claim 12, wherein the lowering end point of the reset pulse is changed according to the rising end point of the reset pulse.   15. The driving method of the plasma display apparatus according to claim 14, wherein the lowering end point is changed according to the rising end point of the reset pulse in the at least one subfield. 20. The driving method of the plasma display apparatus according to claim 19, wherein the lower end of the reset pulse is earlier in time and the lower end of the reset pulse is earlier in a lower gray level subfield.